About MP3 Players: All of them work with Macintosh, because they all act as a standard USB harddisk which ANY OS can read/write today.

That's hardly true anymore. Sony's players need Sony software (windows only). iRiver's newer players need Windows Media Player 10 (a surprise change that bit me when I bought one, to return it later). iPods need iTunes. Sure files can be copied to them with explorer/finder/konqueror/cp but those files can't then be played. Most players today need the songs to be loaded into a database by some proprietary software before being used.

Some of Samsung's players remain an exception, which is why I use them. That and .ogg support (I must be one of the few with any significant amount of songs in .ogg format, if the usual comments on that subject are to be believed). The box still says they need Media Player 10, but that is only for DRMd WMVs. (the iRiver player I had for a short period needed WiMP 10 for everything).

All of that is hardly a reason to avoid purchasing a Macintosh of course. iPods (by far the most popular) will of course work, as will Samsung's and some others. It's far from true though that all MP3 players will work with OSX (or Linux, which is why it concerns me).

Well okay honestly I didn't know that. I know about the iRivers though, I saw a really cool one, but the guy at the shop told me it needs Windows XP (XP, not even 2k works!!). But I definitely avoid such crap, I mean damn, I want to use MY player everywhere I want. It happens that I go to a friend, he has a few good songs for my for my walk home and I want to copy them. With such players I first had to install some software on his computer - which is probably what this all is about, avoiding that you use your player too much in such a way. The number one MUST HAVE for an player for me is that it works as a standard USB drive, without ANY kind of extra software involved, and that it can play OGG files. So luckily, you found somebody who also has most of his music in OGG format - welcome to the club, we're at least two so far ;-)

Just for interests sake, could you specify which iRivir player you purchased? I have a H340 and it doesn't need any software at all. I just copy all my oggs/mp3s onto the drive and everything is cool. I haven't tried this on Linux, but on OS X it works just fine. I do remember iRiver talking about using WiMP10, but I think that applies only for ppl who can't sync music collections manually (drag and drops).